[translate] Fix shutdown race for translate ranker model loader.

components/translate/core/browser/translate_script_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/translate/core/browser/translate_script.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/strings/stringprintf.h"
+#include "base/test/scoped_task_scheduler.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
 #include "components/translate/core/browser/translate_download_manager.h"
 #include "components/translate/core/common/translate_switches.h"
 #include "net/base/load_flags.h"
 #include "net/base/url_util.h"
 #include "net/http/http_request_headers.h"
 #include "net/url_request/test_url_fetcher_factory.h"
+#include "net/url_request/url_request_test_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
 namespace translate {
 
 class TranslateScriptTest : public testing::Test {
  public:
   TranslateScriptTest() : testing::Test() {}
 
  protected:
   void SetUp() override {
     script_.reset(new TranslateScript);
     DCHECK(script_.get());
     TranslateDownloadManager::GetInstance()->set_application_locale("en");
+    TranslateDownloadManager::GetInstance()->set_request_context(
+        new net::TestURLRequestContextGetter(
+            base::ThreadTaskRunnerHandle::Get()));
   }
 
   void TearDown() override { script_.reset(); }
 
   void Request() {
     script_->Request(
         base::Bind(&TranslateScriptTest::OnComplete, base::Unretained(this)));
   }
 
   net::TestURLFetcher* GetTestURLFetcher() {
     return url_fetcher_factory_.GetFetcherByID(TranslateScript::kFetcherId);
   }
 
  private:
   void OnComplete(bool success, const std::string& script) {
   }
 
+  // Sets up the task scheduling/task-runner environment for each test.
+  base::test::ScopedTaskScheduler scoped_task_scheduler_;
+
+  // The translate script.
   std::unique_ptr<TranslateScript> script_;
+
+  // Factory to create programmatic URL fetchers.
   net::TestURLFetcherFactory url_fetcher_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TranslateScriptTest);
 };
 
 TEST_F(TranslateScriptTest, CheckScriptParameters) {
   Request();
   net::TestURLFetcher* fetcher = GetTestURLFetcher();
   ASSERT_TRUE(fetcher);
 
@@ skipping 55 matching lines @@
   ASSERT_TRUE(fetcher);
 
   GURL expected_url(script_url);
   GURL url = fetcher->GetOriginalURL();
   EXPECT_TRUE(url.is_valid());
   EXPECT_EQ(expected_url.GetOrigin().spec(), url.GetOrigin().spec());
   EXPECT_EQ(expected_url.path(), url.path());
 }
 
 }  // namespace translate